Merge branch 'main' into feature/pashub-heat-emitter-code-1556

datatypes/epc/domain/mapper.py

@@ -5939,7 +5939,9 @@ def _map_main_building_part(
         wall_construction=main.walls_construction_type,
         wall_insulation_type=main.walls_insulation_type,
         wall_thickness_measured=main.wall_thickness_mm is not None,
-        party_wall_construction=main.party_wall_construction_type,
+        party_wall_construction=_pashub_party_wall_construction_int(
+            main.party_wall_construction_type
+        ),
         sap_floor_dimensions=_map_floor_dimensions(measurements.main_building.floors),
         wall_thickness_mm=main.wall_thickness_mm,
         roof_insulation_location=roof_location,
@@ -5963,7 +5965,9 @@ def _map_extension_building_part(
         wall_construction=ext_c.walls_construction_type,
         wall_insulation_type=ext_c.walls_insulation_type,
         wall_thickness_measured=ext_c.wall_thickness_mm is not None,
-        party_wall_construction=ext_c.party_wall_construction_type,
+        party_wall_construction=_pashub_party_wall_construction_int(
+            ext_c.party_wall_construction_type
+        ),
         sap_floor_dimensions=_map_floor_dimensions(ext_m.floors),
         wall_thickness_mm=ext_c.wall_thickness_mm,
         roof_insulation_location=roof_location,
@@ -7093,6 +7097,33 @@ def _pashub_heat_emitter_code(emitter_label: str) -> Union[int, str]:
     if code is None:
         raise UnmappedPasHubLabel("heat emitter", emitter_label)
     return code
+# PasHub surveyed `party_wall_construction_type` label → SAP10 party-wall code
+# (RdSAP 10 §5.10 Table 15) that `u_party_wall` consumes. Same target codes as
+# the GOV.UK-API (`_API_PARTY_WALL_CONSTRUCTION_TO_SAP10`) and Elmhurst
+# (`_ELMHURST_PARTY_WALL_CODE_TO_SAP10`) siblings — PasHub just lodges the full
+# human label. `0` is the explicit "unknown" sentinel (u_party_wall → 0.25 house
+# / 0.0 flat); `None` is "no party wall / no lodging".
+_PASHUB_PARTY_WALL_CONSTRUCTION_TO_SAP10: Dict[str, Optional[int]] = {
+    "Solid Masonry, Timber Frame, or System Built": 3,  # U=0.0
+    "Cavity Masonry, Unfilled": 4,  # U=0.5
+    "Cavity Masonry, Filled": 11,  # U=0.2 (WALL_CAVITY_FILLED_PARTY)
+    "Unable to determine": 0,  # unknown sentinel → u_party_wall default
+    "Not applicable": None,  # no party wall
+}
+
+
+def _pashub_party_wall_construction_int(label: Optional[str]) -> Optional[int]:
+    """Resolve a PasHub surveyed `party_wall_construction_type` label to its SAP10
+    party-wall code at the mapper boundary. A blank label is "no lodging" and
+    returns None; a non-empty label the lookup does not cover strict-raises
+    `UnmappedPasHubLabel` so the coverage gap is fixed here rather than silently
+    defaulting every party wall to the U=0.25 house value downstream (#1559)."""
+    if label is None or not label.strip():
+        return None
+    key = label.strip()
+    if key not in _PASHUB_PARTY_WALL_CONSTRUCTION_TO_SAP10:
+        raise UnmappedPasHubLabel("party wall construction", label)
+    return _PASHUB_PARTY_WALL_CONSTRUCTION_TO_SAP10[key]
 
 
 def _resolve_elmhurst_underfloor_subtype(

datatypes/epc/domain/tests/test_from_site_notes.py

@@ -1,7 +1,7 @@
 import json
 import os
 from datetime import date
-from typing import Any, Dict
+from typing import Any, Dict, Optional
 
 import pytest
 
@@ -19,7 +19,7 @@ from datatypes.epc.domain.epc_property_data import (
     ShowerOutlet,
     ShowerOutlets,
 )
-from datatypes.epc.domain.mapper import EpcPropertyDataMapper
+from datatypes.epc.domain.mapper import EpcPropertyDataMapper, UnmappedPasHubLabel
 from datatypes.epc.schema.tests.helpers import from_dict
 from datatypes.epc.surveys.pashub_rdsap_site_notes import PasHubRdSapSiteNotes
 
@@ -34,6 +34,46 @@ def load(filename: str) -> Dict[str, Any]:
         return json.load(f)  # type: ignore[no-any-return]
 
 
+class TestPartyWallConstructionCoding:
+    """`from_site_notes` must int-code the PAS Hub `party_wall_construction_type`
+    label to the SAP10 code `u_party_wall` consumes (RdSAP 10 Table 15), not copy
+    the raw label. A raw label reads as `None` and every party wall silently takes
+    the U=0.25 house default — phantom heat loss on the ~165/205 "solid" party
+    walls that should be U=0.0 (Guinness cohort, issue #1559).
+    """
+
+    @pytest.mark.parametrize(
+        "label, expected_code",
+        [
+            ("Solid Masonry, Timber Frame, or System Built", 3),  # U=0.0
+            ("Cavity Masonry, Unfilled", 4),  # U=0.5
+            ("Cavity Masonry, Filled", 11),  # U=0.2 (party-wall-only code)
+            ("Unable to determine", 0),  # unknown sentinel → u_party_wall 0.25 (house)
+            ("Not applicable", None),  # no party wall
+            ("", None),  # no lodging
+        ],
+    )
+    def test_label_maps_to_sap_code(
+        self, label: str, expected_code: Optional[int]
+    ) -> None:
+        data = load("pashub_rdsap_site_notes_example1.json")
+        data["building_construction"]["main_building"][
+            "party_wall_construction_type"
+        ] = label
+        survey = from_dict(PasHubRdSapSiteNotes, data)
+        result = EpcPropertyDataMapper.from_site_notes(survey)
+        assert result.sap_building_parts[0].party_wall_construction == expected_code
+
+    def test_unknown_label_strict_raises(self) -> None:
+        data = load("pashub_rdsap_site_notes_example1.json")
+        data["building_construction"]["main_building"][
+            "party_wall_construction_type"
+        ] = "Reinforced Adamantium"
+        survey = from_dict(PasHubRdSapSiteNotes, data)
+        with pytest.raises(UnmappedPasHubLabel):
+            EpcPropertyDataMapper.from_site_notes(survey)
+
+
 class TestFromSiteNotesExample1:
     """
     Fixture: pashub_rdsap_site_notes_example1.json
@@ -472,7 +512,7 @@ class TestFromSiteNotesExample1:
                     wall_construction="Cavity",
                     wall_insulation_type="As built",
                     wall_thickness_measured=True,
-                    party_wall_construction="Cavity Masonry, Unfilled",
+                    party_wall_construction=4,  # "Cavity Masonry, Unfilled" → SAP10 code 4 (U=0.5)
                     sap_floor_dimensions=[
                         SapFloorDimension(
                             room_height_m=2.37,